Illuminated instrument



4, 1964 D. J. BLACKWELL ILLUMINATED INSTRUMENT Filed June 12, 1962 IN VEN TOR. DancL J. B lac Kwe \1 United States Patent 3,143,098 ILLUMINATED INSTRUMENT Dana .I. Blackwell, Naugatuck, Conm, assignor to Lewis Engineering Company, Naugatuck, Conn, a corporation of Connecticut Filed June 12, 1962, Ser. No. 281,870 8 Claims. (Cl. 116-429) This invention relates to the illumination of indicator devices, and more particularly to dial and pointer illumination in meters and similar indicating instruments.

The invention concerns improvements in the illurninated instruments of my Patents Nos. 2,874,671 and 2,914,021 entitled respectively Illuminated Meter and Illuminated Indicating Means and Instruments, dated respectively February 24, 1959, and November 24, 1959. In these patents there are light-piping members and small lamps, which are used to illuminate the instrument dials and also to bring light to the pointers.

The present invention involves somewhat similar devices, but these are organized and arranged in a different, novel manner to provide more effective light with greater simplicity of parts. In the earlier of my two patents above identified four lamps are utilized to light the dial, two being also utilized to illuminate the pointer; in the later patent two lamps are utilized, with only one lighting the pointer. v

By the present invention greater illumination of the dial and pointer is had-than in the later patent, and the pointer illumination is equal and possibly better than that in my earlier patent, all utilizing a total of but three lamps.

Accordingly, an object of the invention is to provide a novel and improved illuminated meter or instrument dial and pointer, wherein maximum use is made of a plurality of lamps to effect the desired lighting.

Another object of the invention is to provide an improved illuminated instrument as above, which is relatively small and compact so that it requires but little space to effect the illumination.

A further object of the invention is to provide an improved illuminated instrument as characterized, which involves relatively few components of simple construction, thereby to make possible a low fabrication and assembly cost.

A feature of the invention resides in the provision of an improved illuminated instrument of the kind indicated, wherein failure of any one lamp will not render the lighting system inoperative but instead will still permit readings to be had in darkness.

Other features and advantages will hereinafter appear.

In the drawings accompanying this specification, similar characters of reference are used to designate like components throughout the several views, in which:

FIG. 1 is a front elevational view of an illuminated meter as provided by the invention.

FIG. 2 is an enlarged fragmentary axial sectional view through the meter.

FIG. 3 is a transverse vertical sectional view through the instrument, taken on the section line 3 3 of FIG. 2.

FIG. 4 is a transverse vertical sectionalview taken on the front of the pivot portion of the pointer 14 to block stray, undesired light.

Referring to FIG. 2, the pointer 14'is shown as constituted of a solid piece of transparent or clear plastic subice stance, carried by a supporting arm 18 having at its front end a clip 20 embracing and holding the pointer at a point slightly spaced from the pivotal axis thereof. The supporting arm 18 has reverse bends 22 and 24 approxlmately midway between its ends, and extends rearward from the bends 22, 24 for securement to the movable system 26 of the meter. The broken line 28 represents the axis of turning of the pointer 14 and also of the movable system 26, as will be understood.

The dial 12 has suitable indicia as shown in FIG. 1, and

is adapted to be illuminated by light striking it from the rear. Various engraved and/or painted dial structures already well known in the art may be utilized for the dial 12.

To the rear of the dial 12 and in front of the movable system 26 there is located a base plate 30, secured by studs 32 and 34 respectively to the dial 12 and to the stationary portion of the instrument movement. The base plate 30 has a large circular central bore 36 through which the supporting arm 18 extends and in which it can swing or turn to provide an arc of movement for the pointer 14 of approximately 270.

The dial 12 has a somewhat smaller but still relatively large central bore 38 through which the arm 18 passes, such bore being lined by alight sealing bushing or sleeve 40 whereby stray illumination from the lamps shortly to be described is prevented from passing forward through the central opening of the dial.

The plastic pointer 14 is so constituted, as in my patents identified, that a beam of light passing forward through the center bore 38 of the dial 12 and striking a small flat rear surface 42 on the pointer will be reflected by a planar light reflecting surface or means 44 so as to illuminate the pointer along substantially its entire length.

In accordance with the present invention, novel and improved illumination means are provided for producing an effective illumination of the dial 12 and pointer 14. This improved illumination of the dial 12 and the pointer 14 is had in spite of utilizing a relatively small number of bulbs, in the present instance three, and in spite of requiring relatively few components of simple construction and low cost.

As seen in FIGS. 2 and 3, the three small incandescent lamps 48, 50 and 52 are mounted on the base plate 30, being substantially equispaced about the axis 28 of the instrument whereby they are separated by at least and preferably by a somewhat larger angle.

The lamps 48, 50 and 52 are carried in receptacles 54 mounted in suitable openings in the base plate 30, as seen in FIG. 2. All three of the lamps have their filaments located forwardly of the base plate 30, and all three lamps provide light which strikes the rear of the dial 12, effecting an adequate illumination of the same and the indicia carried thereby. Two of the lamps, namely the lamps 50 and 52, are also utilized to provide a dual-strength illumination of the pointer 14.

Thus, with the present arrangement the dial 12 receives light from all three of these lamps whereas the pointer additionally obtains light from two of the said three lamps. Further, the arrangement is such that if one of the tWO lamps 50, 52 supplying light to the pointer becomes inoperative or burned out, the remaining lamp will still provide sufficient illumination to enable the pointer to be readily visible in the dark, and such remaining lamp in conjunction with the remaining third lamp would also be sufficient to illuminate the dial 12 to the extent where indications could be readily obtained.

In providing the dual-light illumination of the pointer the invention provides a unique and surprisingly simple structure which is characterized in the main by an elongate, solid light-piping member 56 which is located at the rear of the dial 12 and which extends between the lamps 50 and 52, with the extremities of the member disposed adjacent the lamps to receive light therefrom. The light-piping member 56 has dual, juxtaposed reflectors intermediate the ends thereof, the said reflectors preferably comprising polished flat surfaces 58 and 60 shown as being located at right angles to each other. The flat reflecting surfaces 58 and 60 reflect the light which is received from the lamps 50 and 52 to a single direction which is upward when viewing FIG. 3 so as to form a combined beam which is adaptable for being directed forward through the panel 12 and at the light-reflecting means or surface 44 of the pointer 14. The means which conducts light from the lamps 50, 52 to the pointer alsoincludes a solid, laterally projecting light-piping portion 62 of the member 56, said portion extending from the side of the member 56 which is opposite to that containing the dual reflectors 58 and 60.

As seen in FIG. 2, the laterally projecting portion 62 extends upward somewhat past the axis 28 of the instrument, and its upper extremity comprises a planar reflecting surface 66 shown as disposed at an angle of 45 with respect to the instrument axis 28. Further, the light piping means may advantageously include a light conducting solid 68 which is secured to the front of the inner extremity of the laterally projecting portion 62. The light conducting solid 68 extends forward and into the opening 38 of the dial 12, terminating just short of the rear surface 42 of the pointer 14.

The members 56, 62 and 68 may be advantageously constituted of light-conducting plastic substance, and all may be in the form of clear solids or else one or several may be tinted. It has been found advantageous, where a tinting of the light beam is desired to provide colored illumination for the pointer 14, to make the light conducting solid 68 of a tinted plastic. Such material may have a red coloring or a blue coloring, to provide either red lighting for the pointer or lunar-White light. Where all of the members 66, 62 and 68 are of perfectly clear and colorless plastic substance, the pointer will be illuminated with unfiltered light.

I have found that the light-piping member 56 and the lateral projection 62 thereof may be constituted of a single piece of material, and may be readily fabricated by a molding procedure. The light-conducting solid block 68 may be cemented to the portion 62, and with such organization the solid or block 68 may readily be of a different material, and may readily have a diiferent coloring or tinting to provide the desired lighting conditions.

It will now be understood that as the pointer 14 travels throughout its arc of movement, the rear planar surface 42 thereof will remain at the axis 28 of the instrument, and for all rotative positions of the pointer will receive light from the light-conducting solid 68, such light being reflected from the planar surface 66 and the surfaces 58 and 60, and originating at the lamps 5i) and 52. With this arrangement, the light from both of the lamps is combined as a single beam, passing through the solid plastic structures 62 and 68 and thence through the air gap between the front face 70 of the block 68 to the pointer 14.

By the above organization, failure of either one of the lamps 50 or 52 will cut off approximately one-half of the light from the pointer 14, but the remaining light will still enable the pointer to be readily visible in the darkness, and the two lamps which remain operative will also provide sufficient lighting for the dial 12 to enable readings to be readily obtained.

With a total of but three bulbs there is thus provided a high level of illumination of the dial 12 while at the same time the point 14 receives light from two of the bulbs with an intensity which is also considered to be of a high level. Moreover, as already mentioned, failure of one of the bulbs will not result in the total extinguishment of light from the pointer, but instead the light will be cut approximately in half, enabling the pointer to be still readily visible in darkness.

The organization by which the above is accomplished is seen to involve relatively few components, which are capable of being economically fabricated and assembled.

Any suitable means for bringing current to the lamps 48, 5t and 52 may be utilized. As seen in FIG. 4, stamped concentric metal conducting rings 74 and 76 may be provided at the rear of the base 30 for connection with the terminals of the lamp receptacles. Terminals 78 and 80 are provided respectively for the rings 74 and 76, to energize these. In place of stamped concentric metal rings, a printed circuit arrangement could be provided; for example, the rings 74 and 76 may be formed by a printing procedure rather than by metal stamping.

Unique means for mouting the light-piping members are provided by the invention. These comprise a metal bracket 82 which is secured to the base plate 30 by screws 84, the bracket having a pair of clamps 86 adapted to receive and frictionally hold the two end portions of the light-piping member 56.

Variations and modifications may be made within the scope of the claims, and portions of the improvement may be used without others.

I claim:

1. An illuminated indicating instrument comprising, in combination:

(a) a dial having indicia thereon, said dial being adapted for lighting from the rear,

(b) a pair of spaced-apart lamps located to the rear of the dial, to eflect rear lighting thereof,

(0) a pointer movable over the front of the dial and having a light-reflecting means adjacent its pivotal axis and an illuminable area along its length, by which the pointer may be lighted by a light beam directed at it from the rear of the dial,

(d) a substantially straight elongate, solid light-piping member having opposite extremities, said member being located at the rear of the dial and extending between the said lamps with the said extremities of the member disposed adjacent the lamps to receive light therefrom, said member having a deep V-notch with substantially planar sloping reflective faces disposed in one side intermediate its extremities, said notch having a depth which is commensurate with the distance between said one side and the opposite side of the member,

(e) said sloping faces meeting each other along a common line and constituting a pair of dual, juxtaposed substantially planar reflector means on the lightpiping member and in the said notch intermediate the said extremities of the member, for reflecting solid beams of light of appreciable thickness and substantially parallel rays received individually in opposite directions from the said lamps, as substantially similar beams which are directed both in a single direction laterally of the member to form a combined beam which has been reflected but once and which is of substantially double strength, said combined beam being adaptable for reflection forward through the dial and at the light-reflecting means of the pointer, thereby to light the latter with at least one beam strength regardless of whether both of the lamps are operative or only one is operative.

2. An illuminated indicating instrument as in claim 1,

wherein:

(a) the light-piping member has a solid laterally-projecting light-piping portion extending from the dual reflector means, receiving the reflected light therefrom and combining the same in a solid material to form the said combined beam.

3. An illuminated indicating instrument as in claim 2,

wherein:

(a) there is a reflector at the extremity of the laterally-projecting portion, for changing the direction of the combined beam into parallelism with the axis of the pointer.

4. An illuminated indicating instrument as in claim 3, 7. An illuminated indicating instrument as in claim 6,

wherein: wherein:

( ere is a light-conducting solid connected to the (a) there are mounting means for the light-piping said extremity of the laterally-projecting portion and member, comprising a metal bracket having clamps extending forward therefrom toward the dial, said 5 engaged with end portions of the member. solid carrying the combined light beam to a point 8. An illuminated indicating instrument as in claim 3, adjacent the light-reflecting means of the pointer. wherein:

5. An illuminated indicating instrument as in claim 4, (a) there is an additional lamp located behind the dial,

wherein: all said lamps being disposed in a plane parallel to (a) the light-conducting solid is tinted to impart color 10 th plane f the dial, and

to the combined light beam. (b) said lamps being substantially equispaced circum- 6. An illuminated indicating instrument as in claim 2, ferentially about the axis of the dial.

wherein:

( the g -P p member and the a a y- References Cited in the file of this patent 121g 125321213111 thereof have a configuration 11ke the let- 15 UNITED STATES PATENTS (b) the said dual reflectors comprise planar surfaces 2,278,520 Klein et 1942 of the member, disposed at right angles to each other 2,237,605 Dlckefson ell 111116 1942 at the side of the member opposite to that from 2,589,569 Peters et a1 Mali 1 1952 which the light-piping portion projects. 20 2,914,021 Blackwell et al. Nov. 24, 1959 

1. AN ILLUMINATED INDICATING INSTRUMENT COMPRISING, IN COMBINATION: (A) A DIAL HAVING INDICIA THEREON, SAID DIAL BEING ADAPTED FOR LIGHTING FROM THE REAR, (B) A PAIR OF SPACED-APART LAMPS LOCATED TO THE REAR OF THE DIAL, TO EFFECT REAR LIGHTING THEREOF, (C) A POINTER MOVABLE OVER THE FRONT OF THE DIAL AND HAVING A LIGHT-REFLECTING MEANS ADJACENT ITS PIVOTAL AXIS AND AN ILLUMINABLE AREA ALONG ITS LENGTH, BY WHICH THE POINTER MAY BE LIGHTED BY A LIGHT BEAM DIRECTED AT IT FROM THE REAR OF THE DIAL, (D) A SUBSTANTIALLY STRAIGHT ELONGATE, SOLID LIGHT-PIPING MEMBER HAVING OPPOSITE EXTREMITIES, SAID MEMBER BEING LOCATED AT THE REAR OF THE DIAL AND EXTENDING BETWEEN THE SAID LAMPS WITH THE SAID EXTREMITIES OF THE MEMBER DISPOSED ADJACENT THE LAMPS TO RECEIVE LIGHT THEREFROM, SAID MEMBER HAVING A DEEP V-NOTCH WITH SUBSTANTIALLY PLANAR SLOPING REFLECTIVE FACES DISPOSED IN ONE SIDE INTERMEDIATE ITS EXTREMITIES, SAID NOTCH HAVING A DEPTH WHICH IS COMMENSURATE WITH THE DISTANCE BETWEEN SAID ONE SIDE AND THE OPPOSITE SIDE OF THE MEMBER, (E) SAID SLOPING FACES MEETING EACH OTHER ALONG A COMMON LINE AND CONSTITUTING A PAIR OF DUAL, JUXTAPOSED SUBSTANTIALLY PLANAR REFLECTOR MEANS ON THE LIGHTPIPING MEMBER AND IN THE SAID NOTCH INTERMEDIATE THE SAID EXTREMITIES OF THE MEMBER, FOR REFLECTING SOLID BEAMS OF LIGHT OF APPRECIABLE THICKNESS AND SUBSTANTIALLY PARALLEL RAYS RECEIVED INDIVIDUALLY IN OPPOSITE DIRECTIONS FROM THE SAID LAMPS, AS SUBSTANTIALLY SIMILAR BEAMS WHICH ARE DIRECTED BOTH IN A SINGLE DIRECTION LATERALLY OF THE MEMBER TO FORM A COMBINED BEAM WHICH HAS BEEN REFLECTED BUT ONCE AND WHICH IS OF SUBSTANTIALLY DOUBLE STRENGTH, SAID COMBINED BEAM BEING ADAPTABLE FOR REFLECTION FORWARD THROUGH THE DIAL AND AT THE LIGHT-REFLECTING MEANS OF THE POINTER, THEREBY TO LIGHT THE LATTER WITH AT LEAST ONE BEAM STRENGTH REGARDLESS OF WHETHER BOTH OF THE LAMPS ARE OPERATIVE OR ONLY ONE IS OPERATIVE. 